Referring initially to FIG. 1, chains 100 have historically been used in dragline buckets 102 in the hoist and drag circuits. Some rigging configurations also use chains in the dump circuit (single dump block systems). Chains 100 have in the past been cast, forged, comprised structural plate, etc.
These chains comprise a plurality of links that are interconnected and engage each other in the region called the “bite” region of the links. This usually corresponds to the inside radial portion of an end of the chain link. This area is subjected to tension loads in use and/or abrasion from the material located in the work area. Over time, this bite region may wear down, compromising the strength of the chain link, and therefore, of the chain as a whole. Consequently, the chain may need to be replaced.
Similarly, the middle portions (sometimes referred to as “rails”) of the chain link, situated between the ends of the chain link may also be subject to wear from abrasion from the material located in the work area, necking due to tensile loads, etc. Once the middle portion of the chain link becomes too thin, the chain link strength and the overall chain strength may be compromised. Consequently, the chain may need to be replaced.
Current practices to monitor these various types of wear include inspection methods to determine when the chains need to be replaced, rotated ninety degrees, or flipped. In some cases, gauges, measuring tapes, and calipers may be employed to determine if a minimum dimension of the chain link has been reached. When inspecting the bite region on the chain links, it may be necessary to pry the chain link apart to measure and inspect. This can be time consuming and may damage the chain undesirably.
Accordingly, it is desirable to develop a better method for inspecting chain links for wear than has yet been devised.